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问题 选择题

物体做匀加速直线运动，加速度为2m/s2，那么（　　）

①物体的末速度一定比初速度大2m/s

②每秒钟物体的速度增加2m/s

③第3秒初的速度比第2秒末的速度大2m/s

④第3秒末的速度比第2秒初的速度大4m/s．

A．①②

B．②④

C．①④

D．②③

答案

①加速度为2m/s2，任意一秒内物体的末速度一定比初速度大2m/s，故①错误

②每秒钟物体的速度增加2m/s，故②正确

③第3秒初和第2秒末是同一时刻，故③错误

④第3秒末的速度比第2秒初的速度大4m/s，故④正确

故选B．

问答题

The teaching of English as a second language (ESL) in schools has had a history of conflicting arguments, interesting innovations and some very positive methodological changes. To understand the present situation, it is necessary to consider the past and the wider educational context which has a bearing on it.

Until quite recently, approaches to ESL work have been ply influenced by methods developed to teach English as a foreign language to older learners. These methods placed much emphasis on drills, exercises and remedial programs that focus on language in abstraction. 46) The prescriptive nature of such methods and the demands they made on the teacher’s time developed the belief that ESL work could be tackled only by the specialist ESL teacher working with small groups of children. Such an approach does not fit comfortably into current notions of learning and teaching in the primary school, nor does it sufficiently equip ESL learners in the secondary school to benefit from normal schooling. 47) In prescribing what language is to be taught, it has ignored what children bring to the learning task and the choices they make about how and what they want to learn. Furthermore, the location and organization of language provision did not measure up to the demand. 48) The language centers and English language services all contributed to providing special and concentrated teaching of English as a second language in small groups, varying in size from four or five to fifteen. Whatever the pattern of provision, the main aim was to give pupils sufficient English to enable them to join normal schools as quickly as possible. The success of such special provision depended very much on the close and constant liaison of language teachers with the subject teachers and the class teachers and on the continuity of learning experiences provided by them. 49) One of the important disadvantages of language centers and withdrawal groups was that ESL children were being taught away from those English- speakers who provide the most powerful models, i. e. their peer group. Peer-group interaction is an important element in any learning situation, but its particular strengths in a classroom with ESL learners cannot be overemphasized.

50) The separation of second language learners from the mainstream classroom cannot easily be justified on educational grounds, since in practice it leads to both their curriculum and language learning being impoverished.

47) In prescribing what language is to be taught, it has ignored what children bring to the learning task and the choices they make about how and what they want to learn.
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单项选择题

当机械的主激振频率低于支承系统一阶固有频率的支承称（）。

A、刚性支承

B、柔性支承

C、弹性支承

D、悬空支承
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